1. Field of the Invention
The present invention relates to a bulk container for flowable materials and, more specifically, to a flexible bulk container system which is stackable both in use and in storage, and is collapsible to facilitate more compact storage and transportation.
2. Description of the Prior Art
It is known in the art to provide rigid containers, such as drums, for the storage and transportation of flowable materials. Such prior art drums, however, are bulky and heavy, even when not in use. Also, by utilizing the strength attributes of a circular exterior, such drums do not maximize space most efficiently. Accordingly, when such drums are placed on a pallet, there are substantial open interior spaces, which could be better utilized to store flowable materials.
It is also known in the art to reduce weight by providing a container of a flexible, circular construction, which may be collapsed for transportation and storage after use. While such containers utilize space somewhat more efficiently than drums, are somewhat lighter than drums, and may be reduced in size for storage, such containers do not maximize the available space for storage of flowable materials. Additionally, since such containers do not possess rigid sides, they cannot be stacked, thereby substantially reducing their ability to maximize utilization of warehouse space.
While it is known in the art to provide rigid, square containers, maximizing the space allocation and allowing for the containers to be stacked, such containers are typically heavy, expensive, and difficult to collapse for storage or transportation when not in use.
It is also known in the art to provide collapsible containers with rigid side supports to allow for the containers to be stacked. One drawback associated with this construction is that such containers typically require strapping material or other securement mechanisms to be provided across the top of the container, thereby reducing access to the top of the container and preventing the container from being used in association with many flowable material filling systems. Also, such containers are typically of a cylindrical construction, thereby preventing them from utilizing space most efficiently.
It is further known in the art to provide stackable collapsible containers which have a top and bottom panel for receiving tubular supports which extend therebetween. The tubular supports are typically provided with cross bracing which adds strength, but which also adds cost, weight, complexity and difficulty in assembly, disassembly and storing the container. When it is desired to transport the stackable collapsible container in the collapsed orientation, the tubular supports and top panel are provided within the bottom panel. As the top panel is required to be of dimensions sufficient to fit inside the perimeter of the bottom panel, the top panel is necessarily smaller than the bottom panel. When the containers are stacked near one another for transport, with the bottom panels in contact with one another, the top panels of adjacent containers necessarily have a space therebetween. This space, although small, prevents such prior art containers from obtaining lateral support from the top panel of an adjacent container. The filled containers are typically being transported in a rail car or the like. When the rail car stops or starts suddenly, the space between the top panels of the containers allows the containers to generate momentum, causing the top panels of the containers to sway into and out of contact with one another. These undesired torsional forces lead to damage and possible failure of the container.
Accordingly, it is desirable to provide a container for flowable materials which is of a low cost, lightweight construction, easily collapsible for storage and transportation when not in use. It is also desirable to provide a container for flowable materials which provides a large access area into the container from the top of the container, which is stackable both when in use and when not in use, and when in use provides improved lateral support characteristics both at the bottom and top of the flowable materials container when the container is filled with flowable material. The difficulties encountered in the prior art heretofore are substantially eliminated by the present invention.